The treasure box of the woodturner.

For Woodturning magazine I wrote the following article.

Click on the picture for the article.

 

 

For the woodturner, a well-filled and mixed wood supply is like a kind of a treasure box, a treasure box with rough diamonds, but in this case in the shape of wood.
Like with real diamonds, it’s on the artist to make jewels from the rough stuff.
To get a well-filled and mixed wood supply, takes a lot of time and difficulty and sometimes hard labour. Also a wood supply needs care and maintenance.
As a woodturner, you are always on the search of different species of wood and being alert if there are cutting down trees in your area.
When you have collected some wood, you can’t simply stack it away, it needs to be cut to manageable pieces and/or sawn to planks and most important, sealing the end grain.
So, now you have a good supply of wood, the next thing you gone do is getting inspiration and working out idea’s and see how you can translate this to your pieces of wood.
You whether can work from seasoned wood or you choose to turn green wood, you searching for a good piece of wood for the project you have in mind and discover to your embarrassment that, in spite of your precautionary measures, the wood did split or crack.
Also, there will be some wood witch having so many faults, you don’t know what to do with it.
Many pieces seem to be worthless, but it took so much labour to get and prepare it, it is a shame to throw it away.
Any woodturner will have the experience that, in the process of turning, something is going wrong or the wood is showing up some serious faults, which you didn’t count on, the only option left is to throw the piece away.
But once again, if you put in a lot of work already, it is difficult to do so.

Does this mean end of story ???

The answer is: no it isn’t, there are plenty of options to cope with this kind of situations.

Not only in woodturning, but also in lots of other disciplines and arts, trying to hide a fault is very difficult and if you do so, there is a great chance people will see it anyway.
A badly covered fault will be detrimental to the object.
In most cases, it is much better to highlight the fault, this will give people the idea it was designed like that and therefore will it give a work piece an upgrade rather than a degrade.
It is always a pity to throw wood away where you already put in a lot of work, therefore I developed and used different kind of techniques to rescue apparent worthless pieces of wood and half finished projects.

Below there are some examples of these techniques.

The vase in the right picture was turned from a cherry log, which already was split during drying. (see left picture) To highlight and strengthen the split, it is laced with a leather string. This design was developed previous to the turning.
     

The log of this Yew lidded box had some cracks, which is fairly common for Yew.
I thought I could turn these cracks away, but they didn’t.
Some small cracks are super glued and sanded, the bigger one was covered with copper cramps, which are made from electricity wire.
     
The holes in this Yew vase where designed to be a feature of this vase, but like the lidded box, there was a crack, which couldn’t turned away.
As a solution, I came up with the same design idea like the cherry split vase with the leather lace.
But a leather lace would be to thick, so I stitch the crack with cane.
The holes where very welcome, for I could get in with a long nosed pliers to put the cane trough the holes.
     
This Laburnum bowl was turned from a section of the trunk of the tree, where it was separating in two trunks.
As a slab of wood, it stayed together, but it soon became clear that this wouldn’t stay that way.
In the process of turning the outside, I cut and glued in some Wengé butterfly pieces, to keep the pieces together after turning the inside of the bowl.
These butterfly’s where cut in deep enough, so they showed up when turning the inside.

 

How to handle with faults in wood.

The techniques you can use to cope with faults in wood are very various, any turner uses superglue and wood dust or sandpaper to deal with little cracks.
You can highlight cracks and splits with lots of other materials.
There are woodturners / sculptors who make magnificent objects from perfect pieces of wood, but I like to show how you how to make a nice object from a piece of wood you probable would throw away.
In my woodshed I found a piece of Yew, which was extremely suitable for this project, it is full of cracks and splits and has some major bark inclusions.
This Yew was immediate sawn to planks after cutting and has been stored for 12 years.
I like the capriciousness of Yew, but with this piece I didn’t now what to do whit it, until I came up with the idea to write a story of this subject.
This article will show you it is not always necessary to throw away bad pieces of wood.

Picture 1

 

This is the piece of Yew which I gone to work with.
In my enthusiasm, I was forgotten to take pictures of the rough piece, so putting it quickly back together.
About 2-3 inches from the underside there is a major bark inclusion visible.
This would give me some problems later on.
Picture 2

 

The backside of this piece.
The dimensions are: 40 cm. in diameter x 10 cm. (16 x 4 inches)
Picture 3

 

The backside of this piece was reasonable flat, so I used a big sanding disc to put it against with pressure of the tailstock.
Picture 4 Picture 5 Picture 6
These pictures showing the main problems that I had to deal with, big cracks, bark inclusions and on one side is still the pit visible.
It is no more then a very bad piece of wood.
 
Picture 7

 

First job, balancing the piece, this is done with 300-400 rpm.
For some time I installed a frequency inverter with a triple phase motor, this is coming in very handy now, with this inverter you can very fine-tune the speed of your lathe just below the point of shaking of the lathe.
Picture 8

 

This is the topside of the bowl, to turn the underside first, you have to flip over the disc.
To do this, I created a flat area on the topside to mount this side on a screw chuck.
Picture 9

 

The disc is turn over and mounted on a screw chuck.
It is a big piece of wood to mount on a screw chuck, but drilling the hole a little smaller as usual, you get a very firm grip.
Picture 10

 

The disc is cleaned up, I’m now shaping the bottom of the bowl, using a 13 mm / ½ inch bowl gouge.
This kind of turning is not always without risks, as I would discover later on.
Wearing face protection isn’t a luxury, with this kind of turning I do use it always.
Picture 11

 

The faults showing up.
Bark inclusion, cracks and the heart still in one side of the disc.
Picture 12

 

Here is a major bark inclusion visible, which also visible is in picture 1 and 6.
I tried to fix this with lots of medium viscosity superglue.
Picture 13

 

A close-up of the bark inclusion.
Picture 14

 

This is the opposite of the inclusion, this is gone to be the topside of the bowl.
In spite of all the superglue, with turning out the inside of the bowl, this piece came of.
With a firm blow at my upper arm, it went to the other side of my workshop.
The next day, my wife asks me why my arm was so blue, I didn't dare to tell her what happened.
Picture 15

 

And some more cracks.
Picture 16

 

A branch with bark inclusion.
Picture 17

 

The heart still present on one side of the bowl, with a
surrounding crack in one annual ring.
Picture 18

 

The outside nearly in shape, a tennon is turned which is gone be held in the large gripper jaws from my scroll chuck.
Picture 19

 

The big cracks and bark inclusions are fixt with superglue.
I’m not worried about staining the wood by the glue, there will be more turning, which will remove these stainings.
Picture 20

 

Some of the bigger cracks are gone be fixed with butterfly key’s.
From Laburnum I made some butterfly blocks, these where drawn over across the cracks.
Picture 21

 

Chiselling out the holes for the butterfly keys is purely handwork.
If you want them to show on the inside to, you have to make the holes deep enough.
Picture 22

 

The butterfly key’s glued in place.
I use polyurethane glue, this will fill up any gap, which can occur with hand chiselling.
With the aid of two clamps and a lath, I glued back a broken out piece of the foot.
Picture 23

 

It was extremely difficult to get a good finish from the tool by the low speed I was turning.
The disc was still heavily in unbalance and therefore I couldn’t speed up the lathe.
I balanced the disc with some pieces of lead, this would let me turn the bottom at a higher speed with a much better result.
Picture 24

 

Power sanding with a 125 mm. / 5 inch sanding pad in a drill.
I used sanding disc from 120 grit up to 400 grit and finished hand sanding with 600 grit.

Picture 25

 

A lot of cracks and splits have to be super glued and sanded. To prevent staining the wood by the glue, one thin coat of sanding sealer or oil is being applied before applying the superglue, this will prevent staining the wood by the glue.
Stainings from the superglue are very difficult to be sanded away.

Picture 26

 

Reversing the disc onto the large gripper jaws of my four jaw chuck.

Picture 27

 

The disc reversed to turn the inside of the bowl.
Because of the many cracks and splits, it’s very important to cut the wood on a proper way, no aggressive cuts are used on turning the rim.
Keeping the handle well down, I’m cutting with the wing of the gouge and the wing is almost vertical.

Picture 28

 

In this way you get a very fine cutting action, like a skew chisel.
Keep the bevel rubbing and cutting from the centre outwards.
(Hollowing the inside is of course from the rim to the centre.)
This picture is made with a flashlight, therefore it looks like the bowl is standing still, but you can see the shavings coming of.

Picture 29

 

This picture shows clearly the piece, which was coming of, with some polyurethane glue, it was glued back in place.
Somewhat lower, a branch with some bark inclusion.
(the same one as from picture 16)

Picture 30

 

On behalf of the bad shape of this piece of Yew, I decided to make the rim very simple and putting a metal hoop around it to keep the pieces together.
With an angle grinder, I cut two stripes from a sheet of metal.
From these two stripes I will make the hoop.

Picture 31

 

The two stripes of sheet metal are made to the same width as is the flat outside of the rim, which is 18 mm.
The sheet metal I had in stock, wasn’t long enough to make the hoop from one stripe, so I cut two of them.
The ends are joint together with some rivets.

Picture 32

 

The rivets I used are homemade from nails.
In a piece of scrap metal I drilled a hole, the same diameter as the shaft of the nails, which are 2 mm.

Picture 33

 

The head of the nail is hammered flat to give it a look of a hand forged rivet.

Picture 34

 

With three rivets, the ends are joint together.
The length of the rivets is about 1 mm. longer as is the thickness of both stripes.

Picture 35

 

The hoop completed, to get the hoop tight over the bowls rim, it is made about 2 mm. shorter as the circumference of the rim.
With the ancient technique of “weel making”, the hoop is put on the bowl.

Picture 36

 

Don’t try to make the hoop to the right dimension, it is much easier to make the hoop 2-3 mm. smaller and turn down the rim of the bowl until the hoop fits almost.

Picture 37

 

This is about the right size of the hoop, it just doesn’t fit.
In this situation, the hoop will be approximately 1 mm. shorter as is the circumference of the rim.

Picture 38

 

By heating the metal, the hoop will expand and will easily fit over the rim.
When the metal cools down, it will shrink and the hoop gets a very tight fit.
You don’t need to heat the metal very hot, just a good warming up will do.

Picture 39

 

This very tight fit is not enough to keep things together.
I intended to fix the hoop with some hand-forged nails.
This was not only a matter of design, but the nails will also make sure, the “loose” part of the rim will stay on its place.

Picture 40

 

I had some hand forged nails in store, but they needed a little more shaping.
The underside of the heads weren’t flat, so the nails would protrude to much after mounting in the rim.

Picture 41

 

To make the underside of the nail heads flat, I used the same technique as making the rivets.
A hole is drilled in a piece of scrap metal, the nail is dropped in and the head is hammered flat.
This will not only make the underside of the head flat, but it will give the top of the head a more hand forged look.

Picture 42

 

It’s obvious not possible to hammering the nails simply in the rim of the bowl, the bowl wouldn’t survive this action.
For this application, they where also to long and have to be cut to the right length.

Picture 43

 

Holes are drilled to accept the nails, drilling about 1 mm. bigger as the biggest diameter of the shaft of the nail.
An easy way to divide the holes is, putting some tape around the rim, cut to length, take it of and divide on the tape the drilling holes.
Put the tape back on the rim and pencil over the markings.

Picture 44

 

The holes are filled with hot glue from a glue gun.
The glue serves not only to holding the nails, but it prevents the wood from staining by the metal nails.

Picture 45

 

To press the nails in the hot glue is not a good idea, by quickly cooling down of the glue by pressing in a cold metal nail, there is a risk you get the nail not al the way in.
It works much better to fill all the holes with glue first.
Heating the nails with a blowtorch and they will easily pushed in and the excess of glue will coming out.
This gives you the guarantee the nail sits like a rock and the head flat on the hoop.

Picture 46

 

Pushing in the nails, after cooling down, the excess of glue can best be removed with a knife.

Picture 47

 

The hoop ready mounted with hand-forged nails.
Turning the inside of the bowl is done in the usual way.
The butterfly keys are showing up on the inside.

Picture 48

 

A close-up of the bad side of the bowls rim.
This “loose” piece of the rim is not only held in place by the polyurethane glue, but also by two nails in the rim.

Picture 49

 

A close-up of the butterfly key, fixing a split.

Picture 50

 

I wasn’t quit sure what to do with the big split from the ”loose” piece of the rim, until I discovered a jar with some metal grindings of a key cutting machine, which I saved some years ago.
This could be mixed with epoxy to fill up the split.

Picture 51

 

This was a failure, I thought putting enough grindings in the mixture but it wasn’t.
Besides this, the mixture reacted so fast, it was hardening before I could apply it all.

Picture 52

 

After about a half hour, I cut the not yet fully hardened out mixture away with a carving gouge to a deepness of 2-3 mm.
Next I put the pure metal grindings in the split and soaked it with superglue.
This gave me the result I wanted.

Picture 53

 

With a scraper, the excess of the filling is turned away and the inside of the bowl is power sanded with sanding pads held in a drill.
The same procedure is used for the bark inclusion in the bottom of the bowl.
It can be necessary to repeat this action to get the split completely filled with the grindings.

Picture 54

 

The finished inside of the bowl with a single coat of oil.
The bowl is set aside for a period of about 2 months in my basement, where is a ideal climate to let the wood settle.
In spite of the 12 years storage time, the wood will move and cracks will appear again.
So you can better save your energy to the time the wood is stable.

Picture 55

 

A close-up of the metal inlay.

Picture 56

 

To finish turn the bottom, I made a rechucking disc from a board of oak. (this had accidental the right size)
Some plywood blocks are screwed on and turned to size to holding the bowl firmly.
Much care is to be taken here, because there is more air as there is wood to turn.

Picture 57

 

The bottom of the bowl finished with one coat of oil.

Picture 58

 

After the wood has stabilised, it can be finished off.
All the cracks that are palpable need to be super glued and sanded.
The finishing will prevent the wood from staining by the glue, but if the crack needs more glue after sanding, first lightly oil the wood again with a tissue.
Finally sand the bowl with a 1000 grit wet and dry sanding paper and sanding the oil into the wood.

Picture 59

 

The bowl completely finished.

This is the “diamond”, which is created from a apparent worthless piece of wood.

Picture 60

 

Another example of the same technique.